Xiaohuai XUE
,
Luhai WU
,
Bainian QIAN
,
Jingli LI
,
Songnian LOU
材料科学技术（英文）
X80 pipeline steel produced by TMCP has high strength and high toughness with ultrafine grain microstructure. The microstructure coarsens and the toughness worsens at the coarse grained (CG) HAZ apparently after weld simulation. The experimental results indicated that the bainitic ferrite and the second phases formed at cooling are differently as the variation of carbon in base metal. In low carbon steels, the bainitic ferrite laths are long and narrow, the second phases are complex including residual austenite, martensite, the M-A constituent and the Fe3C carbide. The formation of Fe3C carbide is the main reason of the poor toughness in CG HAZ. The ultralow carbon in base metal, however, can improve the CG HAZ toughness through restraining the formation of carbides, decreasing the M-A constituent, increasing the residual austenite content, which are beneficial to the CG HAZ toughness.
关键词:
X80 pipeline steel
,
null
,
null
,
null
,
null
LI Chong-wei
,
CHENG Guo-guang
,
WANG Xin-hua
,
ZHU Guo-sen
,
CUI Ai-min
钢铁研究学报(英文版)
A mathematical model in present study has been established to investigate the effect of Rheinstahl Heraeus (RH) blow argon mode on the decarburization rate in ultra-low carbon steel refining based on the RH equipment of Shougang Qian′an Iron and Steel Co Ltd (SQISCO). The calculated results show that the increase of argon flowrate promotes the carbon elimination from argon gas bubble surface, molten steel free surface in vacuum as well as splash droplet surface, while reduces that from the interior of liquid steel. It has been found the critical turning point of flowrate ascension is at the 5th minute and the optimum blow argon flowrate in later stage is 2100 L/min in accordance with the 2 stages argon blow mode, which have been confirmed in the commercial production in SQISCO.
关键词:
RH
,
vacuum
,
mathematical model
,
argon flowrate
,
decarburization
